Panasonic EY7552 VI. Maintenance, VII. Tightening Torque, Factors Affecting Tighten­ ing Torque

VI. MAINTENANCE

•Use only a dry, soft cloth for wiping the unit. Do not use a damp cloth, thinner, benzine, or other volatile solvents for cleaning.

•In the event that the inside of the tool or battery pack is exposed to water, drain and allow to dry as soon as possible. Carefully remove any dust or iron filings that collect inside the tool. If you experience any problems operating the tool, consult with a repair shop.

VII. TIGHTENING

TORQUE

The power required for tightening a bolt will vary, according to bolt material and size, as well as the material being bolted. Choose the length of tightening time accordingly.

Reference values are provided below. (They may vary according to tightening conditions.)

Factors Affecting Tighten­ ing Torque

The tightening torque is affected by a wide variety of factors including the followings. After tightening, always check the torque with a torque wrench.

1)Voltage

When the battery pack becomes nearly discharged, the voltage decreases and the tightening torque drops.

N・m	M16, M20, M24 x 45 mm
	Standard bolt
（㎏f-cm）

600M16,M20,M24×45 mm

（6122）

500 （5102）

torque	400				M24
Tightening	（4082）
	300			M20
	（3061）
	200			M16
	（2041）
	100
	（1020）
	0.0	0.5	1.0	1.5	2.0	2.5	3.0
			Tightening time (Sec.)

M16, M20, M24 x 45 mm

N・mHigh tensile bolt

（㎏f-cm）

	600	M16,M20,M24×45 mm
	（6122）		M24
	500
torque	（5102）
			M20
	400
Tightening	（4082）
	300
			M16
	（3061）
	200
	（2041）

100 （1020）

0.0 0.5 1.0 1.5 2.0 2.5 3.0

Tightening time (Sec.)

Bolt Washer

Steel plate thickness 10 mm

Nut Washer Spring washer

Tightening conditions

•The following bolts are used. Standard bolts: Strength type 4.8 High tensile type 12.9

Explanation of the strength type

4.8

Bolt yield point

(80% of tensile strength) 32 kgf/mm2 (45000 psi)

Bolt tensile strength 40 kgf/mm2 (56000 psi)

2)Tightening time

Longer tightening time results in increased tightening torque. Excessive tightening, however,­ adds no value and reduces the life of the tool.

3)Different bolt diameters

The size of the bolt diameter affects the tightening­ torque.

Generally, as the bolt diameter increases, tightening torque rises.

4)Tightening conditions

•Tightening torque will vary, even with the same bolt, according to grade, length, and torque coefficient (the fixed coefficient indi­ cated by the manufacturer upon produc­

tion).

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